Stability and Activity of Rhodium Promoted Nickel-Based Catalysts in Dry Reforming of Methane

The rhodium oxide (Rh(2)O(3)) doping effect on the activity and stability of nickel catalysts supported over yttria-stabilized zirconia was examined in dry reforming of methane (DRM) by using a tubular reactor, operated at 800 °C. The catalysts were characterized by using several techniques including nitrogen physisorption, X-ray diffraction, transmission electron microscopy, H(2)-temperature programmed reduction, CO(2)-temperature programmed Desorption, and temperature gravimetric analysis (TGA). The morphology of Ni-YZr was not affected by the addition of Rh(2)O(3). However, it facilitated the activation of the catalysts and reduced the catalyst’s surface basicity. The addition of 4.0 wt.% Rh(2)O(3) gave the optimum conversions of CH(4) and CO(2) of ~89% and ~92%, respectively. Furthermore, the incorporation of Rh(2)O(3), in the range of 0.0–4.0 wt.% loading, enhanced DRM and decreased the impact of reverse water gas shift, as inferred by the thermodynamics analysis. TGA revealed that the addition of Rh(2)O(3) diminished the carbon formation on the spent catalysts, and hence, boosted the stability, owing to the potential of rhodium for carbon oxidation through gasification reactions. The 4.0 wt.% Rh(2)O(3) loading gave a 12.5% weight loss of carbon. The TEM images displayed filamentous carbon, confirming the TGA results.